1. Field of the Invention
The present invention relates to a chuck and a tube joint. In particular, the present invention relates to a chuck preferably usable to form a tube joint simply and inexpensively, and to the tube joint having the chuck.
2. Description of the Related Art
A tube joint comprises a tubular first tube joint member, a tubular second tube joint member which is to be coupled to the first tube joint member, a sleeve which is attached to a connecting portion between the first and second tube joint members and which is used to couple and uncouple the first and second tube joint members, a compressive coil spring which urges the sleeve in a direction to couple the first and second tube joint members, and an engaging means which engages the first and second tube joint members with each other.
The engaging means includes a plurality of steel balls provided in the first tube joint member, such that the steel balls are inserted into an annular groove formed on the surface of the second tube joint member for engagement. However, such engaging means using the steel balls as described above has a complicated structure, in which the assembling operation is complicated.
In view of the background as described above, a chuck provided on a first tube joint member is suggested as follows. The chuck has an annular ring portion, and extends along a central axis of the annular ring portion. Ends of the annular ring portion have roll-shaped engaging portions. The ends of the engaging portions are engaged with an annular groove of a second tube joint member (see, for example, Japanese Laid-Open Patent Publication No. 2000-314411). By using such a chuck, for example, it is possible to improve production efficiency of the tube joint and reduce production cost.
However, the above-mentioned chuck requires extra rolling process in production including a large number of winding operations, in order to sufficiently secure the strength of the ends. Further, the annular ring portion, which serves as a base portion of the engaging portions, is formed by deep drawing. Therefore, it is demanded to further reduce the cost for machining these portions.